Underground pipelines are commonly used throughout the world to transport various materials from one location to another. Conventionally, the pipes which eventually form the pipeline system are provided with a protective coating at some point prior to burial. This protective coating deteriorates over time thereby necessitating the removal of the deteriorated coating and application of a new protective coating to prevent the pipeline from being damaged.
A variety of methods and devices have been proposed and implemented for excavating an underground pipeline and refurbishing the deteriorated coating formed thereon. The conventional manner for excavating the underground pipeline is through the use of a backhoe. This manner of unearthing an underground pipeline has a number of drawbacks. Specifically, during the unearthing process, the backhoe is likely to strike the pipeline thereby damaging the same. Further, it is especially difficult and time consuming to clear the earth from underneath the underground pipeline so that a coating removal device may ride freely on the pipeline.
Similarly, once the underground pipeline has been unearthed, conventional techniques for removing the deteriorated coating therefrom have been fraught with design flaws which sacrifice economies of time, labor and money. Known techniques for removing deteriorated coating include assemblies which use spring loaded knife blades connected to a rotating ring driven concentrically around the pipe. This system is disadvantageous in that, once the coal-tar coatings become pliable, they tend to build up on the knife blades rendering the blades incapable of effectively removing deteriorated coating. This in turn results in significant delays, while the knife blades are cleaned. Still other systems have required the pipeline to be removed from the burial ditch prior to removal of the protective coating.
Upon excavating the underground pipeline and removing the deteriorated protective coating, the exterior surface of the pipeline must be examined to determine if the pipeline was damaged during either process or became damaged prior thereto. Known methods for examining the pipeline are extremely antiquated and inefficient. Commonly, the inspection is performed by individuals visually examining the external surface of the pipeline. Mirrors are used so that individuals can see the lower sections of the pipeline. It will be readily appreciated that visual inspection is extremely unreliable and expensive.